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In this research we investigated the contact angle of commercial SnAgCu solder paste mixing with some carbon allotropes such as graphite, graphene quantum dots, and fullerene of varying concentrations with melting temperature, wettability, interfacial microstructure. The wettability was assessed in terms of the contact angle. The in-line digital holography was used for determining the contact angle and morphological of samples at each temperature which the samples have been heating from room temperature until the melting temperature. In the experiment, only one beam was used as the object and reference beams which recorded by a CMOS camera. The recorded image was reconstructed by the angular spectrum digital holography numerical programing. Using the reconstructed images of our results, the shape and contact angle of solder pastes can be investigated.

The effect of the papaya latex on the visibility of fingerprint was investigated. The fingerprints of the thumb without and with touching papaya latex for 5 and 10 min were prepared on the glass slides and captured by CMOS camera. The fingerprint images were reconstructed and the transverse intensity profiles were performed. The valley depth and the ridge width for these prepared fingerprints were determined. The results show that the visibility of the fingerprints increased with increasing touching time with papaya latex. It can be concluded that the finger surface needed to be scanned using any fingerprint sensors should be touched with papaya latex for about 10 min before image scanning to increase the image quality.

We present the design and testing of a prototype in-plane echelle spectrograph based on an actively controlled fibre-fed double-pass design. This system aims to be small and efficient with the minimum number of optical surfaces - currently a collimator/camera lens, cross-dispersing prism, grating and a reflector to send light to the detector. It is built from catalogue optical components and has dimensions of approximately 20x30 cm. It works in the optical regime with a resolution of >70,000. The spectrograph is fed by a bifurcated fibre with one fibre to a telescope and the other used to provide simultaneous Thorium Argon light illumination for wavelength calibration. The positions of the arc lines on the detector are processed in real time and commercial auto-guiding software is used to treat the positions of the arc lines as guide stars. The guiding software sends any required adjustments to mechanical piezo-electric actuators which move the mirror sending light to the camera removing any drift in the position of the arc lines. The current configuration using an sCMOS detector provides a precision of 3.5 milli-pixels equivalent to 4 m/s in a standard laboratory environment., 21 pages, 9 figures, 2 tables, accepted PASP

The EXOplanet high resolution SPECtrograph (EXOhSPEC) instrument is an echelle spectrograph dedicated to the detection of exoplanets by using the radial velocity method using 2m class telescopes. This spectrograph is specified to provide spectra with a spectral resolution R < 70, 000 over the spectral range from 400 to 700 nm and to reach a shortterm radial velocity precision of 3 m/s. To achieve this the separation between two adjacent spectral orders is specified to be greater than 30 pixels and to enable a wide range of targets the throughput of the instrument is specified to be higher than 4%. We present the results of the optimization of the spectrograph collimator performed and initial tests of its optical performance. First, we consider the spectrograph design and we estimate its theoretical performance. We show that the theoretical image quality is close to the diffraction limit. Second, we describe the method used to perform the tolerancing analyzes using ZEMAX software to estimate the optical performance of the instrument after manufacturing, assembly and alignment. We present the results of the performance budget and we show that the estimated image quality performance of EXOhSPEC are in line with the specifications. Third, we present the results of the stray light analysis and we show that the minimum ratio between the scientific signal and the stray light halo signal is higher than 1,000. Finally, we provide a status on the progress of the EXOhSPEC project and we show the first results obtained with a preliminary version of the prototype.

Applying of a phase-shifting digital holography combined with compressive sensing to inspect the soldering quality of surface mount technology (SMT) which is a method for producing electronic circuits. In SMT, the components are mounted and connected with each other directly onto the surface of printed circuit boards (PCBs). By reconstructing the multidimensional images from a few samples of SMT, the results are solved by an optimization problem. In this paper, two problems have been concerned. The first one is to examine the devices and the soldering quality of connections between them, which are in micro-scaled. The second is to observe the effect of heat treatment of soldering material and devices on the surface mount board.

In this paper we propose a modern technique to evaluate the shape changes of solder paste by using double-view in-line digital holography. We observed the transformation of three different kinds of solder paste composition: pure solder paste, solder paste mixed with 0.02%, 0.05%, 0.10% graphene (GPN) and 0.02%, 0.05%, 0.10% graphene oxide (GPNO), respectively. The shape of the solder pastes was investigated at different melt temperatures (i.e. 200°C, 250°C, and 300°C) for 30 seconds using a collimated beam propagating through the solder paste, then being double reflected on a mirror and second incident on another sides of the solder paste. The double images bearing beams were recorded with a CCD sensor simultaneously. The single recorded digital hologram from double view technique was reconstructed using digital holography. The results show that the double-view technique provides reliably data. Moreover, it would be developed for observing more than two images by single holography writing in the future.

This article proposes and shows that a low-optical-power laser when arranged in a zigzag fashion in a free space can create strong air thermal stress and form a chemical-free optical net that is capable of repelling adult mosquitoes away. Experimental proof of concept using a pointer-like diode-pump solid-state laser (447 nm wavelength and 500 mW maximum) and reflective sheets shows that all 80 adult Aedes albopictus mosquitoes are completely trapped inside the open glass chamber. Most of the adult mosquitoes prefer to stay near the bottom of the open glass chamber as it is cooler than the top part that contains several zigzagging laser beams. Reducing air thermal stress via increasing the spacing between the two adjacent laser beams allows the adult mosquitoes to easily escape out of the zone of the laser beams.